Hello, I set about building an x100 amplifier mainly to measure noise on power supplies where my scope runs into the noise floor. This is my first attempt. Bandwidth is -3dB at 185kHz. I hope to improve this by using a better op-amp on order from Digikey. Noise floor with the input terminated 50ohm is about 2mV pk-pk. This could be general noise from my lab, the scope or the cheap cable I used as well as the op-amp. Nevertheless, this equates to roughly 20uV on the input, meaning the amp is only useful for ~100uV of noise or above without averaging. A low-pass filter of ~90kHz was built into the unit and can be switched in and out using a toggle switch. The filter is an active type using two sections of the quad-op-amp. The noise floor is significantly higher when the filter in on, which surprised me. I intend to play with the circuit and see if this can be improved. Your comments, questions and advice are solicited.